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HCN + 3HNO3 → 2N2O3↑ + H2CO3 + H2↑

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Reaction of hydrogen cyanide and nitric acid
HCNHydrogen cyanide + 3HNO3Nitric acid
⟶
2N2O3↑Dinitrogen trioxide + H2CO3Carbonic acid + H2↑Hydrogen

The reaction of hydrogen cyanide and nitric acid yields dinitrogen trioxide, carbonic acid, and hydrogen (Other reactions are here). This reaction is an oxidation-reduction reaction and is classified as follows:

Table of contents
  1. 1Reaction data
  2. 2Thermodynamic changes
  3. 3References
  4. 4Related reactions
  5. 5Related categories

Reaction data

Chemical equation

Reaction of hydrogen cyanide and nitric acid
HCNHydrogen cyanide + 3HNO3Nitric acid
⟶
2N2O3↑Dinitrogen trioxide + H2CO3Carbonic acid + H2↑Hydrogen

General equation

Reaction of reducing species and oxidizing species
Reducing speciesReducing agent + Oxidizing speciesOxidizing agent
⟶
ProductOxidation product + ProductReduction product

Oxidation state of each atom

Reaction of hydrogen cyanide and nitric acid

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
HCNHydrogen cyanide1
Reducing
Reducing
HNO3Nitric acid3
Oxidizing
Oxidizing

Products

Chemical formulaNameCoefficientTypeType in general
equation
N2O3Dinitrogen trioxide2
Redoxed product
–
H2CO3Carbonic acid1
Oxidized
–
H2Hydrogen1
Reduced
–

Thermodynamic changes

Changes in standard condition (1)

Reaction of hydrogen cyanide and nitric acid
◆
ΔrG−182.8 kJ/mol
K1.06 × 1032
pK−32.03
HCNIonized aqueous solution + 3HNO3Ionized aqueous solution
⟶
2N2O3↑Gas + H2CO3Un-ionized aqueous solution + H2↑Gas
Standard enthalpy
of reaction
ΔrH°
kJ · mol−1		Standard
Gibbs energy
of reaction
ΔrG°
kJ · mol−1		Standard entropy
of reaction
ΔrS°
J · K−1 · mol−1		Standard heat
capacity of reaction
at constant pressure
ΔrCp°
J · K−1 · mol−1
per 1 mol of
Equation
−60.7−182.8409.3–
per 1 mol of
−60.7−182.8409.3–
per 1 mol of
−20.2−60.93136.4–
−30.4−91.40204.7–
per 1 mol of
−60.7−182.8409.3–
per 1 mol of
−60.7−182.8409.3–

Changes in standard condition (2)

Reaction of hydrogen cyanide and nitric acid
◆
ΔrG−165.2 kJ/mol
K8.75 × 1028
pK−28.94
HCNIonized aqueous solution + 3HNO3Ionized aqueous solution
⟶
2N2O3↑Gas + H2CO3Un-ionized aqueous solution + H2↑Un-ionized aqueous solution
Standard enthalpy
of reaction
ΔrH°
kJ · mol−1		Standard
Gibbs energy
of reaction
ΔrG°
kJ · mol−1		Standard entropy
of reaction
ΔrS°
J · K−1 · mol−1		Standard heat
capacity of reaction
at constant pressure
ΔrCp°
J · K−1 · mol−1
per 1 mol of
Equation
−64.9−165.2856–
per 1 mol of
−64.9−165.2856–
per 1 mol of
−21.6−55.07285–
−32.5−82.60428–
per 1 mol of
−64.9−165.2856–
per 1 mol of
−64.9−165.2856–

Changes in standard condition (3)

Reaction of hydrogen cyanide and nitric acid
◆
ΔrG−130.1 kJ/mol
K6.20 × 1022
pK−22.79
HCNUn-ionized aqueous solution + 3HNO3Ionized aqueous solution
⟶
2N2O3↑Gas + H2CO3Un-ionized aqueous solution + H2↑Gas
Standard enthalpy
of reaction
ΔrH°
kJ · mol−1		Standard
Gibbs energy
of reaction
ΔrG°
kJ · mol−1		Standard entropy
of reaction
ΔrS°
J · K−1 · mol−1		Standard heat
capacity of reaction
at constant pressure
ΔrCp°
J · K−1 · mol−1
per 1 mol of
Equation
−17.2−130.1378.7–
per 1 mol of
−17.2−130.1378.7–
per 1 mol of
−5.73−43.37126.2–
−8.60−65.05189.3–
per 1 mol of
−17.2−130.1378.7–
per 1 mol of
−17.2−130.1378.7–

Changes in standard condition (4)

Reaction of hydrogen cyanide and nitric acid
◆
ΔrG−112.5 kJ/mol
K5.12 × 1019
pK−19.71
HCNUn-ionized aqueous solution + 3HNO3Ionized aqueous solution
⟶
2N2O3↑Gas + H2CO3Un-ionized aqueous solution + H2↑Un-ionized aqueous solution
Standard enthalpy
of reaction
ΔrH°
kJ · mol−1		Standard
Gibbs energy
of reaction
ΔrG°
kJ · mol−1		Standard entropy
of reaction
ΔrS°
J · K−1 · mol−1		Standard heat
capacity of reaction
at constant pressure
ΔrCp°
J · K−1 · mol−1
per 1 mol of
Equation
−21.4−112.5825–
per 1 mol of
−21.4−112.5825–
per 1 mol of
−7.13−37.50275–
−10.7−56.25413–
per 1 mol of
−21.4−112.5825–
per 1 mol of
−21.4−112.5825–

Thermodynamic data of reactants

Chemical formulaStandard enthalpy
of formation
ΔfH°
kJ · mol−1		Standard Gibbs
energy of
formation
ΔfG°
kJ · mol−1		Standard
molar entropy
S°
J · K−1 · mol−1		Standard molar
heat capacity at
constant pressure
Cp°
J · K−1 · mol−1
HCN (l)108.87[1]124.97[1]112.84[1]70.63[1]
HCN (g)135.1[1]124.7[1]201.78[1]35.86[1]
HCN (ai)150.6[1]172.4[1]94.1[1]–
HCN (ao)107.1[1]119.7[1]124.7[1]–
HNO3 (l)-174.10[1]-80.71[1]155.60[1]109.87[1]
HNO3 (g)-135.06[1]-74.72[1]266.38[1]53.35[1]
HNO3 (ai)-207.36[1]-111.25[1]146.4[1]-86.6[1]
HNO3 (l)
1 hydrate
-473.46[1]-328.77[1]216.90[1]182.46[1]
HNO3 (l)
3 hydrate
-1056.04[1]-811.09[1]346.98[1]325.14[1]
* (l):Liquid, (g):Gas, (ai):Ionized aqueous solution, (ao):Un-ionized aqueous solution

Thermodynamic data of products

Chemical formulaStandard enthalpy
of formation
ΔfH°
kJ · mol−1		Standard Gibbs
energy of
formation
ΔfG°
kJ · mol−1		Standard
molar entropy
S°
J · K−1 · mol−1		Standard molar
heat capacity at
constant pressure
Cp°
J · K−1 · mol−1
N2O3 (l)50.29[1]–––
N2O3 (g)83.72[1]139.46[1]312.28[1]65.61[1]
H2CO3 (ao)-699.65[1]-623.08[1]187.4[1]–
H2 (g)0[1]0[1]130.684[1]28.824[1]
H2 (ao)-4.2[1]17.6[1]577[1]–
* (l):Liquid, (g):Gas, (ao):Un-ionized aqueous solution

References

List of references

  1. 1
    Janiel J. Reed (1989)
    The NBS Tables of Chemical Thermodynamic Properties: Selected Values for Inorganic and C1 and C2 Organic Substances in SI Units
    National Institute of Standards and Technology (NIST)